title: Search for proteins required for accurate gene expression under oxidative stress: roles of guanylate kinase and RNA polymerase.
abstract: In aerobically growing cells, in which reactive oxygen species are produced, the guanine base is oxidized to 8-oxo-7,8-dihydroguanine, which can pair with adenine as well as cytosine. This mispairing causes alterations in gene expression, and cells possess mechanisms to prevent such outcomes. In Escherichia coli, 8-oxo-7,8-dihydroguanine-related phenotypic suppression of lacZ amber is enhanced by mutations in genes related to the prevention of abnormal protein synthesis under oxidative stress. A genome-wide search for the genes responsible, followed by DNA sequence determination, revealed that specific amino acid changes in guanylate kinase and in the β and β' subunits of RNA polymerase cause elevated levels of phenotypic suppression, specifically under aerobic conditions. The involvement of the DnaB, DnaN, and MsbA proteins, which are involved in DNA replication and in preserving the membrane structure, was also noted. Interactions of these proteins with each other and also with other molecules may be important for preventing errors in gene expression.
authors.affiliation: From the Frontier Research Center and Department of Biochemistry, Fukuoka Dental College, Fukuoka 814-0193 and.
authors.forename: Hachiro
authors.initials: H
authors.lastname: Inokuchi
authors.forename: Riyoko
authors.initials: R
authors.lastname: Ito
authors.forename: Takeshi
authors.initials: T
authors.lastname: Sekiguchi
authors.forename: Mutsuo
authors.initials: M
authors.lastname: Sekiguchi
mesh_terms: D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D004258:DNA Polymerase III / Q000235:genetics / Q000378:metabolism; D012321:DNA-Directed RNA Polymerases / Q000235:genetics / Q000378:metabolism*; D053488:DnaB Helicases / Q000235:genetics / Q000378:metabolism; D048168:Escherichia coli K12 / Q000201:enzymology* / Q000235:genetics; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D055106:Genome-Wide Association Study; D006147:Guanine / Q000031:analogs & derivatives / Q000378:metabolism; D051528:Guanylate Kinases / Q000235:genetics / Q000378:metabolism*; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000502:physiology*
chemical_list: D018528:ATP-Binding Cassette Transporters; D001426:Bacterial Proteins; D029968:Escherichia coli Proteins; C079726:MsbA protein, Bacteria; C540081:rpoB protein, E coli; C024829:8-hydroxyguanine; D006147:Guanine; D051528:Guanylate Kinases; C101139:beta subunit, DNA polymerase III; C108570:beta' subunit of RNA polymerase; D012321:DNA-Directed RNA Polymerases; D004258:DNA Polymerase III; C506730:dnaB protein, E coli; D053488:DnaB Helicases
keywords: Gene Expression; Guanylate Kinase; Oxidative Stress; Protein Synthesis; RNA Polymerase; RNA Synthesis